Coaxial ribbon cable connector

ABSTRACT

This invention relates to a connector for multi-unit coaxial cable of the type wherein each center conductor has a individual shield and each shield has a separate drain wire. More particularly, the connector includes a plurality of contact members each of which consists of an opposing cantilever contact spring section for mating with contact elements of other electrical circuits, a dual in-line cantilever, torsion bar terminating section for receiving either the coaxial cable center conductor or the drain wire, a housing to hold the plurality of contact members and a strain relief clamp member.

United States Patent Huber Feb. 4, 1975 [52] U.S. Cl 339/103 M, 339/17F, 339/176 MF [51] Int. Cl H01! 11/20, l-lOlr 13/46 [58] Field of Search339/17, 18, 103, 176, 95-99,

[56] References Cited UNITED STATES PATENTS 3,162,501 12/1964 Wahl339/98 3,189,863 6/1965 Leach 339/17 F 3,235,833 2/1966 339/97 P3,434,093 3/1969 Wedekind 339/17 F 3,663,922 5/1972 Foust, Jr, et al.339/17 F 3,697,925 10/1972 Hensehen 339/17 F 3,707,696 12/1972 Canter339/17 F 3,720,907 3/1973 Asick 339/176 MP Primary Examiner-Roy D.Frazier Assistant Examiner-Terrell P. Lewis Attorney, Agent, or Firm-AMPIncorporated [57] ABSTRACT This invention relates to a connector formulti-unit coaxial cable of the type wherein each center conductor has aindividual shield and each shield has a separate drain wire. Moreparticularly, the connector includes a plurality of contact members eachof which consists of an opposing cantilever contact spring section for-mating with contact elements of other electrical circuits, a dualin-line cantilever, torsion bar terminating section for receiving eitherthe coaxial cable center conductor or the drain wire, a housing to holdthe plurality of contact members and a strain relief clamp member.

1 Claim, 7 Drawing Figures PATENTED FEB 4 5 SHEHIUF 3 PAIENTED 419753.864.011

- SHEET 30F 3 1 COAXIAL RIBBON CABLE CONNECTOR BACKGROUND OFTHEINVENTION Miniaturization, particularly in the electronic industry,created a need to pack in a large number of signalcarrying wire intosmall spaces. In order to avoid having a large number of individualwires coming into a device such as a printed circuit board, flatmulticonductor ribbon cable was developed. Further, in order to preventthe unintentional transfer of electrical signals; i.e., cross-talk,between cables and between individual conductors in a single cable,shielding was incorporated. Such shielding may take the form of a wrapof conducting material around the entire multi-conductor cable; see forexample, US. Pat. No. 3,634,782. Or each individual conductor may beencased in a sheath of conducting material such as disclosed in US. Pat.No. 3,663,739. Although not insurmountable, many problems did develop interminating the shielded multiconductor flat cable, particularly interminating the shielding material itself. These problems led one workerin the field to invent a multi-conductor cable wherein each centerconductor is individually shielded and each shield is provided with adrain wire which is in parallel and in contact with the shielding. Thisinvention. is disclosed in U.S. Pat. application Ser. No. 208,955, filedon Dec. 16, 1971, the contents thereof being incorporated herein byreference. The individual drain wires provided a first step towardsimplified terminating of multi'conductor cable of a coaxial nature;i.e., coaxial ribbon cable. What remained to be done was to invent aconnector which would accomplish the simplified termination.

Accordingly, the present invention provides a connector which consistsof an insulated housing having cavities therein, each cavity adapted toreceive a contact member of the type where one end contains an opposingcantilever spring contact section and the opposite end contains a dualin-line, cantilever, torsion bar wire terminating section.

BRIEF DESCRIPTION OF THE DRAWINGS The invention, together with itsconstruction and method of operation, along with other objects andadvantages thereof, is illustrated more or less diagrammatically in thedrawings, in which:

FIG. 1 is an exploded view of the housing member, strain relief clampmember and a prepared coaxial ribbon cable;

FIG. 2 shows the assembly of the components shown in FIG. 1;

FIG. 3 is a perspective view of the contact member embodying features ofthe present invention;

FIG. 4 is a plan view of one contact member of FIG. 3 positioned in oneof the cavities of the housing member of FIG. 1;

FIGS. 5 and 6 are side views of two contact members, positioned in thehousing member, illustrating the method of terminating the coaxialribbon cable of FIG. 1; and

FIG. 7 shows another embodiment of the contact member of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. I the coaxial ribboncable 10 which is to be terminated to the connector constructed inaccordance with the present invention consists of signal-carrying centerconductors 12, drain wires 14 and suitable insulating material. Thisparticular type coaxial ribbon cable is described in the aforementionedapplication Ser. No. 208,955. Directly in front of cable 10 is housingmember 16 which is molded from an insulating materiaf'such asglass-filled nylon. The external features of housing member 16 includethe housing body 18 bounded on either side by rails 20 which, at oneend, expand outwardly into mounting flanges 22. Each flange 22 has oneforward lug 24, two rearward lugs 26 and a slot 28 all of whichconstitute in cooperation means for retaining cable strain relief clamps40.

Internally housing body 18 contains two rows of cavities 30, one rowabove the other, with each cavity extending through the body. Theinternal structure of the cavities is described below. The externalexpressions of the cavities are contact element entrances 32, seen onthe front face 34 of body 18, and the contact openings 36, the top row'of which is seen running across the rear portion 38 of body 18. Eachcavity is isolated physically and electrically from its horizontal andvertical neighbors. The contact openings 36 begin at the back edge 39 ofthe horizontal surface of body 18 (see FIG. 5).

The two halves a and b of the cable strain relief clamp 40 are shown,one above and the other below housing member 16. Each half contains asurface 42 in which a number of inwardly directed lances 44-are coined.These lances, pointing alternatively forwardly and rearwardly, bite intothe outer insulation of cable 10 to provide the mechanical strainrelief. Forwardly and displaced above surface 42 is lip 46 which coversa row of the contact openings 36 of the housing member when assembled.

On either side of surface 42 is an ear 48 which fit inbetween lugs24-26, on flanges 22. Each ear contains a bore 50 for receiving a bolt52. As the halves are interchangable, only one bore is threaded.

The rear portion 54 of surface 42 is upturned to provide stiffness forthe thin metal stock from which the clamp is made. The piece of metalconnecting lip 46 to surface 42 also provides stiffness to the clamp.

FIG. 2 shows the assembled connector 56.

Each of the aforementioned cavities 30 receive a contact member which isillustrated in FIG. 3 and to which reference is now made.

Contact member 60 is formed from an integral piece of sheet metal,preferably beryllium copper, and plated with gold or other suitableplating metals. Structurally the contact member may be divided into abase 62, an opposing cantilever contact spring section 64 and aterminating section 66, the former located near the front end 68 of thebaseand the latter positioned at the back end 70.

The front end 68 of the base 62 contains a laterally projecting sharptip 72. Another similar tip 73 is pro vided on the same side of the basein the vicinity of terminating section 66.

Opposing cantilever contact spring section 64 include two arms 74-76which slidingly engages a square post (not shown) such as are used toconnect devices to printed circuit boards or other contact elements ofother electrical circuits. The two arms are positionedv on one side ofbase 62 with arm 76 directly overlying arm 74. Arm 76 is supported by astrap 78 which expreferred distance of about five times the thickness ofI the metal sheet. In the making of the contact member, terminal 80 isformed coplanar and parallel to terminal 82 and is then bent and wrappedover the top of base 62. The frist L-shaped terminal 80 is the primarycontact terminal. The second L-shaped terminal 82 provides the strainrelief for the wire being terminated therein and also is a secondarycontact terminal. Each terminal consists of a horizontal part whichparallels base 62 and avertical part which extends upwardly from thehorizontal part. The horizontal part is adapted to receive any twistingor torsional forces which may be applied to the contact member via cable10. The vertical part is adapted to receive any vertical movementimparted thereto by the cable. The slotsin each terminal begin in thetop of the vertical part, such beginnings being beveled to facilitatewire receiving. As is well known in the art, such slots are dimensionedto the conductor or drain wire so that optimum electrical contact isachieved thereinbetween,

Returning to housing body 18 and more particularly to the cavities 30which extend through the body, reference is now made to FIG. 4, a planview ofa cavity and FIG. 5, a cross-sectional view of the body takenalong lines -5 of FIG. 1.

The cavities in the lower row, hereinafter designated as cavities 30 l,are the mirror image of the cavities in the upper row, which cavitieswill be referred to as cavities 30 u.

Cavities 30 are designed to receive therein contact members 60 with theminimum amount of free space. Thus, since contact member 60 is notsymetrical, the cavities are not symetrical. As FIG. 4 shows, entrances32 have a inwardly beveled or funnel-shaped opening to facilitate theinsertion of the square posts or other contact elements. As FIG. 5shows, immediately past the opening, the height of the cavity increasesas evidenced by rearwardly facing shoulders 86, one adjacent the cavityfloor 88 and the other adjacent the cavity roof 90. The increasedvertical dimension remains unchanged from shoulders 86 rearwardly.

The left side wall 92 of the cavities contains an undercut 94 adjacentto floor 88 to accommodate the base 62 of contact member 60. Thisundercut, only slightly larger than the thickness of the base, extendsfrom the cavity entrance rearwardly to about the beginning of thecontact opening 36.

The forward part of the cavity is wide enough to receive the contactspring section 66 which is on the right side of contact member 60.

The middle part of the cavity widens to receive the horizontal platform79.

The rear part of the cavity, which is contact opening 36, is the widestpart and accommodates the dual inline terminals 80-82.

As FIG. 4 shows, the left side wall 92 is the wall which isprogressively cut back to widen the cavities.

As noted above, the lower cavities are' the mirror image of the uppercavities. Thus, with the nonsymetrical'widening described above, whilethe entrances of the two rows of cavities are aligned, one below theother, the 5 contact openings 36 of one row is displaced laterally fromthe other row. This displacement is equal to the distance between centerconductor 12 and drain wire 14 of ribbon coaxial cable 10.

The right side wall 96 remains unchanged from entrance 32 to the end ofcontact opening 36.

Contact openings 36 are opened on the top to permit the insertion of amulti-anvil tool (FIG. 5) and to the rear so that the contact member 60can be slid into the cavity during assembly.

In assembly the preferred embodiment, first, each of the cavities 30 isloaded with a contact member 60, those in cavities 30 u facing in anopposite direction than those in cavities 30 I. As FIG. 4 shows, anyrearward pull on the contact members cause the tips 72-73 to dig intowall 96 and thusly the members are retained in the cavity. The shoulder86 adjacent floor 88 provides a predetermined positioning means for themembers 60 as well as a forward stop means.

Cable is prepared by stripping the outer insulating jacket back toexpose a suitable length of center conductor l2 and drain wire 14.

The exposed lengths of center conductor 12 are placed into contactopenings 36 of cavities 30 u in alignment with terminals 80-82 and theexposed lengths of drain wire 14 are placed into contact openings 36 ofcavities 30 l, also in alignment with terminals 80-82. Two multianviltools 98 are brought into contact with the conductors and wires,pressing them into the slots in the terminals 80-82 as shown in FIG. 6.Thereafter, clamp halves 40 a and b are placed inbetween lugs 24-26 withlip 46 covering the top of contact openings 36. Upon bolting the halvestogether via bolts 52 the assembly is complete as shown in FIG. 40 2.

FIG. 7 illustrates a contact member 60' wherein the contact springsection 64 of contact member 60 is replaced by a contact pin section102. Section 102 includes a U-shaped pin 104 with the opening 106 of theU facing to the side. Legs 108 of the U are closed or pinched togetherat the free end 110 of the pin. The vertical strap 78 and platform 79 isreplaced by a supporting wall 112. In all other respects contact member60 is the same as contact member 60. There are a number of uses forcontact member 60' including that of mating with contact member 60.

Of the several novel features of the housing and its cavities and of thecontact member in its entirety, special note of the cantilever, torsionbar terminating section should be taken. Through the combination of twoterminals, each being flexible in vertical-horizontal directions and intwisting motions, the contact member over-all has a very low verticalprofile which enhances its use in miniaturization applications. Further,the novel features of the present invention provide a means wherebycoaxial ribbon cable may now be terminated easily and with excellentelectrical characteristics.

clearness of understanding only, and no unnecessary limitations shouldbe understood therefrom, as some modifications will be obvious to thoseskilled in the art.

The foregoing detailed description has been given for 6 What is claimedis: the signal-carrying conductor or the drain wire; 1. A connector forconnecting a coaxial ribbon cable and of the type having a plurality ofsignal-carrying conduc- 0. strain relief means for relieving strain onthe coaxtors and drain wires, to contact elements of other eleci l ibbble which may be terminated therein, meal which comprises: at v 5 saidmeans including two identical halves, each half a. a housing ofinsulating material having a plurality having a surface containing aplurality of inwardly 0f Cavities extending thefethfough; projectinglances for engaging the coaxial ribbon a P f i y of members Posltlonedthe cable, some of the lances pointing in one axial di- Favmes mhedhousmg f m 0 rection and other of such lances pointing in the opi onone Contact means or reislhetifly posite axial direction, said halvesfurther having mg contact elements of other electrical circuits andthereon means for being fastened to said housing. on anotherend terminalmeans for receiving either

1. A connector for connecting a coaxial ribbon cable of the type havinga plurality of signal-carrying conductors and drain wires, to contactelements of other electrical circuits, which comprises: a. a housing ofinsulating material having a plurality of cavities extendingtherethrough; b. a plurality of contact members positioned in thecavities in the housing, each contact member having on one end contactmeans for resiliently engaging contact elements of other electricalcircuits and on another end, terminal means for receiving either thesignal-carrying conductor or the drain wire; and c. strain relief meansfor relieving strain on the coaxial ribbon cable which may be terminatedtherein, said means including two identical halves, each half having asurface containing a plurality of inwardly projecting lances forengaging the coaxial ribbon cable, some of the lances pointing in oneaxial direction and other of such lances pointing in the opposite axialdirection, said halves further having thereon means for being fastenedto said housing.